Hydraulic metal extrusion press



July 16, 1968 F. J, KOHNEN 9392,56?

HYDRAULIC METAL EXTRUSION PRESS Filed Aug. 18, 1965 3 Sheets-Sheet 1.

July 16, 1968 F. J. KOHNEN 3,392,567

HYDRAULIC METAL EXTRUSION PRESS Filed Aug. 18, 1965 Y 3 Sheets-Sheet 2 July 16, 41968 F. J. KOHNEN 3,392,567

HYDRAULIC METAL EXTRUSION PRESS Filed Aug. 18, 1965 3 Sheets-Sheet 5 NVEN'OR FKANZ- Tosef l( OIM/6W United States Patent O Frice 3,392,567 HYDRAUHC METAL EXTRUSlON PRESS Franz Josef lohnen, Duisburg, Germany, assigner to Hydraulili G.m.b.l'l., Duisburg, Germany Filed Aug. 18, 1965, Ser. No. 4%,677 Claims priority, application Germany, Aug. 18, 1964, H 53,563 3 Claims. (Cl. 72-253) ABSTRACT OF THE DlS-CLSURE A metal extrusion press includes a main press piston which is mounted within a main press cylinder for movee ment backwardly and forwardly under the control of suitable pressurizing fluid admitted to alternate sides of the cylinder. The main press piston is provided with a hollowed interior portion which receives an inner end of a head which defines a stem piston cylinder and a bore opening at one end for a stem holder. The `stem holder is connected to the stem piston in a manner permitting the retractable movement thereof but not the driving movement thereof. For driving movement, the head is connected to the stem holder so that the head and the main piston together with the stem holder will move together during a pressure stroke. The means for interconnecting the stem holder to the head and the drive piston comprises a rotatable bayonet-type joint which is actuated by iluid pressure means.

This invention relates in general to extrusion presses and in particular to a new and useful hydraulic metal extrusion press having a displaceable press piston with a stem holder carried thereby which is independently movable for the subordinate movements of the stem but is adapted to be iixedly connected with the main press piston during the extrusion process.

Vertical or horizontal hydraulic metal extrusion presses of conventional construction are provided with a press stein which is permanently xed to the main press piston and is movable therewith. This press construction is disadvantageous in that all movement to be effected by the stem must always be effected by the piston which supplies the propulsion power. When pressing with the use of a stem all movements, for example, the forward movement when the machine is empty, the loading ingot, the unloading reverse movement, the unloading and the full reverse movement must be made by the press piston.

The press lpiston thus travels a length which is approxil mately six times the length of the stem. The actual press length is, however, only about one-sixth of the length traveled.

It is obvious that this unnecessary movement of the press piston at the high temperature part of the machine is uneconomical and wear of the material is thus relatively high. Because of the large mass of the piston, it is necessary to use excessive power in the supply of pressure iiuid for such subordinate movements. In addition, in order to effect movements in an empty condition in a rapid manner, the main cylinder connections must be of relatively large diameter. Substantially smaller connections are required for the press stroke only.

The above considerations have led to an attempt to move the main press piston only for the press stroke and its reverse movement. It is known, for example, to swing the stem out from the central press axis position or to effect a parallel movement of the stem, but such arrangements have the disadvantage that a special ingot insertion device is required. In addition such arrangements do not result in any economies.

In accordance with the invention there is provided a 3,392,567 Patented July 16, 1968 press device which includes a main press which is movable only with the main movements of the stem and the secondary movements are accomplished by means of a stem holder which is slidable relative to the main press piston. The stem holder is advantageously slidable within the main press piston, or an extension thereof, under the control of fluid pressure which is admitted to a separate pressure chamber for the control thereof. The Stem holder advantageously is provided with a propulsion piston which is slidable in a separate cylindrical chamber which advantageously may be formed within the interior of the main piston. Means are provided for automatically connecting the stem holder to the main press piston for the actual pressing movement during extrusion. For this purpose the stem holder may be connected to the transverse head by means of a locking device which is preferably oi interengageable bayonet-type elements which are locked under the action of suitable control.

Accordingly, an object of the invention is to provide an improved extrusion press which includes means for holding the stern so that it may be moved independently of a main press piston for subordinate movements but which is lockable with the main press piston and movable therewith during the main extrusion operation.

A further object of the invention is to provide an extrusion press which includes a relatively large size press piston and a stem holder having a piston element Which is slidable in the interior of the main piston and controlled by separate iluid control for displacing the die during subordinate movements thereof and which 4further includes means for locking the stem holder to the main press piston for eiecting the principal extrusion movement of the piston.

A further object of the invention is to provide an extrusion device which is simple in design, rugged in construction and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specic objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. l is a longitudinal section through the main press drive of a hydraulic metal extrusion press constructed in accordance with the invention;

FIG. 2 is a section similar `to FIG. l indicating the outer or end position of the stem holder;

FIG. 3 is an enlarged end elevation of the extrusion press indicated in FlG, l showing the locking mechanism; and

FIG. 4 is a section taken on the line 4--4 of FIG 3.

Referring to the drawings in particular the invention embodied therein comprises a main press drive generally designated l for an extrusion press which comprises a main press cylinder 2 in which is slidable a dierential piston or main press piston 3. One end of the cylinder is provided with an opening 4 which is connected to recoil valve means 5 for supplying fluid under pressure to the interior of the piston in the chamber 50 for effecting movement of the main press piston 3 to the right for extrusion purposes. The opposite end of the cylinder 2 is provided with a conduit 6 for admitting a lluid under pressure to a chamber 52 for moving the main press piston 3 in an opposite direction or reverse direction. A suitable valve 54 is located in the conduit 6 for controlling the fluid pressure to the chamber 52.

In accordance with the invention, a transverse head or stem cylinder generally designated 7 is aiiixed to the diilerential piston 3 and extends into a hollow bore dened therein. The head 7 includes a cylindrical inner portion 7a, an intermediate cylindrical portion or extension 7b and an outer stern positioning portion or head 7c. A stem holder 13 is slidable within the intermediate portion 7b and the end or head portion 7c and it holds a stem 14. Subordinate movements of the stem holder 13 are accomplished in accordance with the invention under the control of a control piston or stem piston 1t) which is slidable within a bore defined within the end cylindrical portion 7a. Control uid for displacing the control piston 10 is admitted through a passage 56 to a chamber 58 for displacing the piston 10 to the right and is admitted to a passage 60 to a chamber 62 for displacing the piston to the left. Suitable valves 64 and 66 are provided in passages 56 and 60, respectively, for supplying fluid under pressure from a suitable source (not shown) for controlling the movement of the piston 10 and the stern holder 13 with the stem 14. The control piston 1) includes a piston rod 12 which is secured thereto and to the stern holder 13. The connection from the stem piston 10 and the piston rod 12 to the stem holder 13 is such as to perform the function of retracting the stem holder but not driving it.

In accordance with a further feature of the invention, at the front end of the head portion 7c there is provided a locking device generally designated 15. The locking device 15 permits connection of the stem holder 13 with the transverse head 7 so that the stem holder may be moved with the differential piston 3 after locking takes place.

As best indicated in FIGS. 3 and 4, the stem holder 13 is provided at its front end with circumferentially spaced teeth 16 which enable locking in the manner of a bayonet lock with teeth 17 of an internally geared disc 17 which is affixed to the head 7 through a connecting ring 18. In order to provide for relative rotation of the parts 13 and 18 to eect interengagement of the teeth 16 and 17, there is provided a piston rod Z2 which is connected to a piston member 23 which is slidable in a fluid cylinder 70 under the control of uid pressure which is admitted through control lines 72 and '74. The piston rod 22 is connected to the head 7 and to the lo-ck disc 17 by means of a pin 19 and a joint member 20. Reciprocation of the piston 23 causes rotation of the disc 17 and the interengaging of the teeth 16 when movement of the differential piston 3 is to be effected. In a similar manner the teeth 16 and 17 may be disengaged.

The stem holder 13 and the transverse head 7 which is connected to the main or differential piston 3 are locked together by the locking device 15 only for the duration of the actual press work and for the retraction. The stem holder 13 is secured against displacement during the locking process and during pressing by means such as a locking pawl (not shown) when the locking operation takes place.

The press construction in accordance with the invention has the following advantages:

(l) The main press cylinder and the main press piston are shorter by approximately 50% of the stroke of conventional presses which means reduction of weight and cost. The over-all length of the press is reduced.

(2) A rapid-drive piston for the idle stroke which is required when not using a filling container may be eliminated.

(3) When pressing with a stern such as stem 14, the main press piston travels only one-sixth of the customary distance. This extends the life of the equipment and wear and tear is reduced accordingly.

(4) The life of the main pumps will be longer.

(5) The lling valve can be replaced by considerably less expensive recoil valve.

(6) The danger of destroying the ingot loading device by the main press is eliminated.

(7) The secondary speeds of the main press drive may be higher in view of the small quantities of masses to be moved.

While a specie embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

I claim:

1. A hydraulic metal extrusion press comprising a main press cylinder, a main press piston axially slidable in said main press cylinder, a head aiiixed to said main press piston defining an inner stem cylinder and having a bore therein, which is open at one end for the passage of a stem therethrough, a stem holder axially movable in the bore of said head, a stem piston co-nnected to said stem holder and axially movable in the stem cylinder of said head for displacing said stern holder independently of said main press piston, fluid pressure means admissible to said main press cylinder for controlling the movement of said main press piston and admissible to said stem cylinder for controlling the movement of said stem holder independently of said main press piston, and locking means carried by said stem holder and said head for locking said main press piston and said head to said stem holder for movement together.

2. A hydraulic metal extrusion press comprising a main press cylinder, a main press piston axially slidable in said main press piston, said main press cylinder having a hollow interior, means for mounting a stem for movement in the hollow interior of said main press piston, uid pressure means for controlling the movement of said main press piston and for controlling the movement of said stern holder independently of said main press piston, and locking means for locking said main press piston to said stem holder for movement together including an internally toothed ring carried by said head, said stern holder having projecting teeth engageable with the teeth of said head in a bayonet fashion.

3. A hydraulic metal extrusion press comprising a main press cylinder having a hollow cylindrical inner portion and an outer hollow head portion, a main press piston axially slidable in said main press cylinder, said main press piston having an inner hollow interior portion and an outer head portion with a base opened at one end, means mounting a stem for movement in the bore of said head portion including a stem holder axially movable in the bore of said head portion, a piston connected to said stem holder and axially movable in the inner hollow interior portion for displacing said stern holder independently of said main press piston, fluid pressure means admissible to said main press cylinder for controlling the movement of said main press piston and admissible to said inner hollow interior portion for controlling the movement of said stem holder independently of said main press piston, locking means for locking said main press piston to said stem holder for movement together including an internally toothed ring carried by said outer head portion, said stem holder having projecting teeth engageable with the teeth of said head in a bayonet fashion, and means for rotating said stern holder and said outer head portion relatively for interengaging the teeth on said ring and said stem holder for locking said stem holder to said outer head portion and to said main piston.

References Cited UNITED STATES PATENTS 9/1959 Reichl 72-263 l/1963 Kent 72-265 

